I see that Bangkok Airways have indicated their intention to fly the Phuket - Hat Yai route starting from October 25th 2015. Phuket Gazette article Several airlines have tried flying the route, Happy Air and Nok Air couldn't make it profitable, Phuket Air did make money but the airline went under after safety issues. Bangkok Air operate with the same size aircraft as Phuket Air did, they're also pretty savvy, so fingers-crossed they prove successful.
Daily expenses are what you make of them...could be $0, could be $100,000. Since everything is going to be paid for, you can save all of your money if you want to. Anyway...this sounds like a scam. Are you paying the agency to find a job for you?